Oxygen lance with a centrally located orifice



ug- 29 .1967 KARL-OTTO ZIMMER 3,338,570

OXYGEN LANCE WITH A CENTRALLY LOCATED ORIFICE Filed Oct. 1, 1964 2 Sheets-Sheet 'l n 2lf\,7a u3 5 iii-12J Allg- 29, 1967 KARL-OTTO ZIMMER 3,338,570

OXYGEN LANCE WITH A CENTRALLY LOCATED ORIFICE Filed Oct. 1, 1964 2 Sheets-Sheet 2 1/\ `J.2 7 7 6,4 ZJFNZ z H20 r 1 l 1 r f\ .9." 7' f f 70 705/5, NZ Z g f/ga United States Patent 3,338,570 OXYGEN LANCE WITH A CENTRALLY LOCATED ORIFICE Karl-Otto Zimmer, Uferstrasse 15, Dillingen, Saar, Germany Filed Oct. 1, 1964, Ser. No.400,786 Claims priority, application Grmany, Oct. 23, 1963,

1o claims. (l. 26a-34) and in actual use in steel producing and refining furnaces.

A serious drawback of such c-onventional lances is that the useful life of the nozzle or head through which the gas issues is extremely short because the material of the nozzle actually burns away so that the lance must be replaced or repaired at frequent intervals with resultant reduction in. the output of the furnace. Also, such con.

ventional lances represent a serious danger to the persons in charge because the disintegration of a nozzle may reach a stage at which the lance allows coolant to escape into the furnace which will lead to explosions as soon as the coolant comes in contact with molten material in lthe furnace. Furthermore, presently utilized lances do vno-t have any means to prevent or to hinder deposition of molten material thereon. Such deposits of molten material will invariably promote disintegration of the nozzle.

Accordingly, it is an important object of the present invention to provide an improved lance whose life expectancy exceeds substantially the life expectancy of all such lances which are known to us at this time and whose life expectancy can be extended in a very simple manner.

Another object of the invention is to provide a lance which can be utilized to admit one or more gases into a Siemens-Martin furnace or another type of furnace for treating molten steel and they like.

A further object of the invention is to construct the nozzle of the improved lance in such a way that the gas or gases issuing from the nozzle automatically prevent or at least hinder the deposition of molten material thereon.

Still another object of the instant invention is to provide a lance whose nozzle is cooled not only by circulating coolant but also by the gas or gases which are conveyed into the furnace, and wherein the direction or ldirections in which the gases issue from the nozzle may be selected and/ or chan-ged in a very simple way.

An additional object of the invention is to provide a nozzle wherein the gas discharging orifices are distributed and dimensioned in such a way that the reaction of crbon monoxide gas with oxygen m-ay be regulated with utmost accuracy to thereby control the temperature of molten material in the furnace.

A concomitant object ofthe invention is to provide a lance which may replace conventional lances-in Siemens- Martin furnaces without necessitating any or by necessitating only minimal .alterations in the construction of the furnace.

A further object of the present invention is to provide -a lance which consists of a small number of simple parts,

wherein a defective nozzle may be replaced by a fresh nozzle, and wherein the regulation of the rate at which one or more gases Iare admitted into the furnace may be effected while the furnace is in actual use.

3,338,570' Patented Aug. 29, 1967 ICC IWith the above objects in view, one feature of the invention resides in the pro/vision of an apparatus for introducing oxygen, nitrogen and/ or other gases into the chamber of a Siemens-Martin oven or a similar furnace. This apparatus comprises an improved lance having at least three concentric steel pipes which together form the shaft of the lance, and a specially configurated nozzle which may consist of copper and is secured to the ends of all but a median pipe and this median pipe is adjacent to'the outer pipe. The two pipes which surround the median pipe define therewith a pair of concentric annular Channels through which water or another coolant may circulate in sucha way that it flows in a direction away from the nozzle while advancing through the channel which is nearest to the outer pipe.

The inner pipe or pipes define one or more passages for admission of one or more gases into and through suitably distributed orifices in the nozzle. The exposed side of the nozzle tip is provided with a recess and with at least one substantially centrally located orice which discharges into the recess to prevent therein accumulations of molten metal or slag. The configuration of the nozzle is such that its wall thicknes-s is at least nearly constant along the entire cross section thereof, i.e., at least that portion of the nozzle which is exposed to highest temperatures will have a constant or nearly constant wall thickness. l,

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved lance itself, however, both as to its construction and the mode of assembling and loperating the same, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of certain specific embodiments with reference to the accompanying drawings, in which:

FIG. 1 is an axial section through the working end of a lance which is constructed and assembled in accordance with a first embodiment of the present invention;

FIG. 2 is an end view of the lance as seen from the underside of FIG. 1; and

FIG. 3 is an axial section through the working end of a modified lance.

Referring to FIGS. l and 2, there is shown the end portion of a lance which is constructed and assembled in accordance with the present invention. This lance serves as a means for blowing oxygen into a Siemens-Martin furnace or the like and comprises a shaft consisting of three concentric steel tubes 1, 2 and 3. The free ends of the outer tube 1 and inner tube 3 rare brazed (as at 6 and 5) or otherwise sealingly secure-d to coaxial annular portions 10, 10a of a specially coniigurated nozzle or head 4 which consists of copper. The lower end of the median pipe 2 is not secured to the nozzle 4 and extends with clearance into the annular space between the annular portions 1.0, 10a so that the pipes 1-3 and the annular portions 10, 10a define between themselves a pair of coolant conveying channels '7, 9 which communicate at 8, i.e., at the free end of the median pipe 2. Such channels allow for forced circulation of water or another coolant which prevents burning of the nozzle 4. In other words, the pipes 1-3 and the annular portions 10, 10a of the nozzle 4 form a cooling jacket which protects certain more exposed parts of the nozzle and the gas which is admitted through a central passage 11 defined by the pipe 3 and annular portion 10a. The annular portion 10y is the outer wall of the nozzle 4, and this nozzle has a centrally located tip 4a provided with a substantially conical or semispherical recess 13 which insures that the wall thickness of the exposed part of the nozzle is substantially constant. The passage 11 discharges yinto a series of six outwardly inclined equidistant orifices 12 which surround the .recess 13 and into a centrally located orifice 14 of smaller diameter which communicates with the recess. As shown in FIG. 2, the discharge ends of the orices 12 form a circle which is concentric with the orifice 14. The number of orifices 12 may be more or less than six, and the orifice 14 may be replaced by two or more centrally located orifices.

FIG. 1 shows that the provision of annular portions 10, a, recess 13 and orifices 12, 14 contributes to the formation of a nozzle with a substantially constant wall thickness along the entire cross section thereof wherein all portions or sections are close to a coolant, i.e., to oxygen or another gas conveyed through the passage 11 and orifices 12, 14, or to water pumped at elevated pressure in directions indicated by arrows 7a, 9a. This means that there is no localized accumulation of heat such as could lead to scaling and other damage to the nozzle. The jet of oxygen issuing from the central orifice 14 effects a highly satisfactory cooling of the central portion of the nozzle and prevents accumulation-s of molten metal or slag in the recess 13. Such molten material is likely to splash in response to admission of oxygen or for another reason.

FIG. 2 shows that some of the orifices 12 are sealed by plugs `18 which may be soldered or otherwise permanently or detachably secured to the nozzle 4. Such plugs 18 serve to control the direction in which oxygen may be discharged from the nozzle so as to avoid, if necessary, direct impingement of oxygen against the wall structure of the furnace.

By mounting the lance in such a way that its axis is inclined with reference to the surface of molten metal, and by regulating the rate at which oxygen issues through the central orifice 14, the operators may control the temperature of the melt by causing complete or nearly complete combustion of carbon monoxide gas.

FIG. 3 illustrates a portion of a modified lance whose shaft includes four concentric steel pipes 1', 2', 3', 15 and a nozzle 4' consisting of copper and having three concentric annular portions 10', 10a', 10b'. These annular portions are respectively brazed to the ends of pipes 1', 3', 15 as shown at 6', 5', 16. The end of the pipe 2' is free and extends into the annular space between the portions 10', 10a' to provide two communicating channels 7', 9'. The pipe 15 is inserted into the pipe 3' and defines a second passage 17 leading to the centrally located orifice 14' which in turn leads to the recess 13' in the nozzle tip 4a. The outwardly inclined orifices 12 surround the recess 13' and communicate with the passage 11' defined by the pipe 3'. The admission of a first gas through the passage 11 may be carried out independently of admission of a second gas through the passage 17, or the admission of the same type of gas through the passages 11', 17 may be effected at different pressures, at different intervals and/or by different means and from different sources. For example, the passage 11 may be used to deliver oxygen to the orifices 12', and the passage 17 may deliver to the orifice 14' and recess 13' a mixture of oxygen and nitrogen such as is necessary to carry out the nitration of steel in the production of tool steel, construction steel and similar products.

In all embodiments of the present invention, the cross section of each of the coolant-conveying channels (7, 9, 7', 9') should be large enough to insure that a substantial quantity of coolant may circulate per each unit of time. Thus, at a pump pressure of 4 k-g./cm.2, the quantity of water or another coolant which is circulated through the nozzle 4 or 4' preferably should not be less than 25 m per hour but may be much more. Also, the cross section of the channel 7 or 7 should preferably equal or approximate the cross section of the channel 9 or 9' to insure uniform cooling of the piping and of the nozzle along the entire circumference of the lance. It goes without saying that the modification shown in FIG. 3 may be replaced by one which provides three or even more passages for one, two or more gases, as long as the wall thickness of the nozzle can remain substantially constant to insure satisfactory cooling.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for Various applications without omitting features which fairly constitute essential characteristics of the generic and specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Lettersv Patent is:

1. In an apparatus for admitting gases into steel furnaces and the like, a lance including a shaft comprising at least three concentric pipes including an outer pipe, a lmedian pipe land a gas conveying inner pipe; and a nozzle having a pair of concentric lannular portions sealingly connected with the ends of said outer and inner pipes but being spaced from said median pipe so that said pipes define between themselves a pair `of communicating coolant-conveying channels, said nozzle including a tip having an outer side provided with a recess and centrally located orifice means communicating with the space surrounded by said inner pipe and arranged to admit into said recess a gas which is conveyed through said space, at least said tip of the nozzle `being of substantially constant wall thickness along the entire cross section thereof and having a plurality of outwardly inclined orifices surrounding said recess and communicating with said gas conveying inner pipe so as to discharge gas therefrom.

2. A lance as define-d in claim 1, wherein said coolantconveying channels are so dimensioned that a coolant which is maintained at .a pump pressure of about 4 kg./cm.2 will flow through said channels at a rate of at least 25 m.3 per hour.

3. In an apparatus for admitting gases into steel furnaces and the like, a lance including a shaft comprising at least three concentric pipes including an outer pipe, a median pipe and a gas conveying inner pipe; a nozzle having a pair of concentric annular portions sealingly connected with the en-ds of said outer and inner pipes but being spaced from said median pipe so that said pipes define between themselves a pair of communicating coolant-conveying channels, said nozzle including a tip having an outer side provided with a recess and centrally located orifice means communicating with the space surrounded by said inner pipe and arranged toadmit into said recess a gas which is conveyed through said space, 4at least said tip of the nozzle being of substantially constant wall thickness along the entire cross section thereof and having a plurality of outwardly inclined equidistant orifices surrounding said recess -and communicating with said gas conveying inner pipe to discharge the gas therefrom; and plug `means provided in at least one of said inclined orifices to effect unsymmetric distribution of gas which issues from said nozzle.

4. A lance as set forth in claim 3, wherein said plug means is soldered to said nozzle.

5. In an apparatus for admitting gases into steel furnaces and the like, .a lance including a shaft comprising lfour concentric pipes including an outer pipe, a median pipe, an inner pipe and an innermost pipe, said inner pipe defining an annular gas conveying passage and said innerrnost pipe defining la second gas conveying passage surrounded by said annular passage; and a nozzle having three concentric annular portions sealingly connected with the ends of said cute-r, inner and innermost pipes but being spaced lfrom said median pipe s-o that said inner and outer pipes define with said median pipe a pair of communicating coolant-conveying channels, said nozzle including a tip having an outer side provided with a recess and with centrally located orifice means connecting the recess with said second passage, at least said tip of the nozzle being of substantially constant wall thickness along the entire cross section there-of and having a plurality of outwardly inclined orifices surrounding said recess -and communicating with said annular passage, said outwardly inclined orifices having respective discharge ends located forwardly of said centrally located orifice means.

6. A lance as set forth in claim 5, wherein the discharge ends of said inclined orifices form a circle which is concentric with said shaft.

7. A lance as defined in claim 5, wherein said nozzle is metallic.

8. A lance as defined in claim 5, wherein said coolantconveying channels are so dimensioned that .a coolant whic his maintained .at a pump pressure of a'bout 4 kg. cm2 will flow through said channels at a rate of at .least 25 m per hour.

9. A lance as `set forth in claim 5, wherein said pipes consist of steel and said nozzle consists .of copper.

10. In an apparatus for admitting gases into steel furnaces and the like, a lance including a shaft comprising four concentric pipes including an outer pipe, a median pipe, an inner pipe and an innermost pipe, said inner pipe defining an annular gas conveying passage and said innermost pipe defining a second gas conveying passage surrounded by said annular passage; and a nozzle thaving three concentric annular portions sealingly connected with the ends of said outer, inner Iand innermost pipes but being spaced -from said median pipe s that said inner and outer pipes define with said median pipe a pair of communicating coolant-conveying channels, said nozzle including a tip having an outer side provided with a recess and with a single centrally llocated orifice connecting the recess only with sai-d second passage, at least said tip lof the nozzle lbeing of substantially constant wall thickness along the entire cross section thereof and having a plurality of out- 10 wardly inclined orifices surrounding said recess and communicating only with said annular passage, said outwardly inclined orifices having respective discharge ends located forwardly of said centrally located orifice.

References Cited UNITED STATES PATENTS 3,043,577 7/1962 Berry 266--34 3,169,161 2/1965 Kurzinski 266-34 X 3,224,749 12/ 1965 Berry 266-34 FOREIGN PATENTS 554,004 1957 Belgium.

I. SPENCER OVERHOLSER, Primary Examiner.

E. MAR, Assistant Examiner. 

1. IN AN APPARATUS FOR ADMITTING GASES INTO STEEL FURNACES AND THE LIKE, A LANCE INCLUDING A SHAFT COMPRISING AT LEAST THREE CONCENTRIC PIPES INCLUDING AN OUTER PIPE, A MEDIAN PIPE AND A GAS CONVEYING INNER PIPE; AND A NOZZLE HAVING A PAIR OF CONCENTRIC ANNULAR PORTIONS SEALINGLY CONNECTED WITH THE ENDS OF SAID OUTER AND INNER PIPES BUT BEING SPACED FROM SAID MEDIAN PIPE SO THAT SAID PIPES DEFINE BETWEEN THEMSELVES A PAIR OF COMMUNICATING COOLANT-CONVEYING CHANNELS, A SAID NOZZLE INCLUDING A TIP HAVING AN OUTER SIDE PROVIED WITH A RECESS AND CENTRALLY LOCATED ORIFICE MEANS COMMUNICATING WITH THE SPACE SURROUNDED BY SAID INNER PIPE AND ARRANGED TO ADMIT INTO SAID RECESS A GAS WHICH IS CONVEYED THROUGH SAID SPACE, AT LEAST SAID TIP OF THE NOZZLE BEING A SUBSTANTIALLY CONSTANT WALL THICKNESS ALONG THE ENTIRE CROSS SECTION THEREOF AND HAVING A PLURALITY OF OUTWARDLY INCLINED ORIFICES SURROUNDING SAID RECESS AND COMMUNICATING WITH SAID GAS CONVEYING INNER PIPE SO AS TO DISCHARGE GAS THEREFROM. 